Handheld computing device

ABSTRACT

A minimum Z height handheld electronic device and methods of assembly is described. The electronic device includes a single seamless housing having a front opening and a cover disposed within the front opening and attached to the seamless housing without a bezel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No. ______[Atty. Dkt. No. APL1P585] filed concurrently herewith and isincorporated herein by reference.

This patent application is related to and filed concurrently with (i)U.S. Provisional Patent Application No. 61/094,811 entitled“ELECTROMAGNETIC INTERFERENCE SHIELDS WITH PIEZOS”, which isincorporated herein by reference and (ii) U.S. Provisional PatentApplication No. 61/094,816 entitled “COMPACT HOUSING FOR PORTABLEELECTRONIC DEVICE WITH INTERNAL SPEAKER”, each of which are hereinincorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates generally to portable computing devices.More particularly, the present invention relates to enclosures ofportable computing devices and methods of assembling portable computingdevices.

2. Description of the Related Art

The outward appearance of a portable electronic device, including itsdesign and its heft, is important to a user of the portable electronicdevice, as the outward appearance contributes to the overall impressionthat the user has of the portable electronic device. At the same time,the assembly of the portable electronic device is also important to theuser, as a durable assembly will help extend the overall life of theportable electronic device and will increase its value to the user.

One design challenge associated with the portable electronic device isthe design of the enclosures used to house the various internalcomponents. This design challenge generally arises from a numberconflicting design goals that includes the desirability of making theenclosure lighter and thinner, the desirability of making the enclosurestronger and making the enclosure more esthetically pleasing. Thelighter enclosures, which typically use thinner plastic structures andfewer fasteners, tend to be more flexible and therefore they have agreater propensity to buckle and bow when used while the stronger andmore rigid enclosures, which typically use thicker plastic structuresand more fasteners, tend to be thicker and carry more weight.Unfortunately, increased weight may lead to user dissatisfaction, andbowing may damage the internal parts

Furthermore, in most portable electronic devices, the enclosures aremechanical assemblies having multiple parts that are screwed, bolted,riveted, or otherwise fastened together at discrete points. For example,the enclosures typically have included an upper casing and a lowercasing that are placed on top of one another and fastened together usingscrews. These techniques typically complicate the housing design andcreate aesthetic difficulties because of undesirable cracks, seams, gapsor breaks at the mating surfaces and fasteners located along thesurfaces of the housing. For example, a mating line surrounding theentire enclosure is produced when using an upper and lower casing. Notonly that, but assembly is often a time consuming and cumbersomeprocess. For example, the assembler has to spend a certain amount oftime positioning the two parts and attaching each of the fasteners.Furthermore, assembly often requires the assembler to have special toolsand some general technical skill.

Another challenge is in techniques for mounting structures within theportable computing devices. Conventionally, the structures have beenlaid over one of the casings (upper or lower) and attached to one of thecasings with fasteners such as screws, bolts, rivets, etc. That is, thestructures are positioned in a sandwich like manner in layers over thecasing and thereafter fastened to the casing. This methodology suffersfrom the same drawbacks as mentioned above, i.e., assembly is a timeconsuming and cumbersome.

Therefore, it would be beneficial to provide a portable electronicdevice that is aesthetically pleasing and lightweight, yet durable. Itwould also be beneficial to provide methods for assembling the portableelectronic device.

SUMMARY OF THE INVENTION

The invention relates, in one embodiment, to a handheld electronicdevice. The handheld electronic devices includes at least a singleseamless housing having a front opening and a cover disposed within thefront opening and attached to the seamless housing without a bezel.

The invention relates, in another embodiment, to seamless housing formedof a single sheet of metal. The seamless housing includes a top opening,an integral bottom and side walls that cooperate to form a cavity incooperation with the top opening, the bottom wall having a curved bottomsurface, the side walls being rounded such that they form a curved sidesurface and an undercut within the cavity, an inside edge of the sidewalls surrounding and defining the top opening, and an outside edge, amounting bracket attached to the bottom wall suitable for securing anelectronic assembly to the bottom wall of the housing and an opening inat least one sidewall having a depth of trim at least greater than thatprovided by the housing alone.

The invention relates to in another embodiment to a small form factorelectronic device that includes at least a seamless housing having anintegral bottom and side walls that cooperate to form a cavity incooperation with a front opening having a flat top surface, the bottomwall having a curved bottom surface, the side walls being rounded suchthat they form a curved side surface and an undercut within the cavity,an edge of the side walls surrounding and defining the front opening anda plurality of electronic assemblies inserted into the seamless housingthrough the front opening and secured to the bottom surface of thehousing, wherein a Z height tolerance of the plurality of electronicassemblies is minimized such that an upper surface of a topmostelectronic assembly is substantially coplanar with the flat top surfaceof the housing.

A method of self centering a topmost glass unit in a small form factorelectronic device is also disclosed. The small form factor electronicdevice is formed of a seamless housing having a front opening having aflat top surface and side walls where an edge of the side wallssurrounds and defines the front opening and wherein the glass unitincludes an environmental seal having a tapered portion, wherein atleast some of the tapered portion of the environmental seal extendsbeyond an inner edge of the front opening. The method can be carried outby, inserting the glass unit into the front opening and self aligningthe glass unit during the insertion by, interacting of the inner edge ofthe front opening that the portion of the environmental seal thatextends beyond the inner edge of the opening, and concurrently with theinteracting of the inner edge and the extended portion of theenvironmental seal, glass unit fasteners cooperating with a lead indevice.

In another embodiment an integrated speaker assembly suitable for use ina small form factor portable hand held device is described. Theintegrated speaker assembly includes at least a piezoelectric speakerarranged to produce at least audible sounds, an acoustic seal having aplurality of acoustic seal gaps that work in cooperation with thepiezoelectric speaker to direct the sound produced by the piezoelectricspeaker to a desired location in the small form factor portable handheld device, and an acoustic barrier arranged to prevent audible soundsleaking to undesired locations in the small form factor electronicdevice.

The invention relates to in another embodiment to a minimum Z heightmounting bracket system to secure an operational component in a handheldcomputing device having a seamless enclosure. The mounting bracketincludes a plurality of sacrificial z adjustment bumps having asacrificial portion arranged along the length of the mounting bracketwherein after the mounting bracket is attached to the seamlessenclosure, a top portion of the seamless enclosure and the sacrificialportion of the sacrificial z adjustment bumps are machined offconcurrently with a drilling a plurality of xy alignment holes, whereinthe machining and the drilling are performed in a single machine set upthereby minimizing alignment tolerance in xy and z directions.

The invention relates in another embodiment to a method of centering aracetrack between a formed edge and an inside edge of a seamlessenclosure used for supporting a handheld computing device. The method iscarried out by optically determining a plurality of reference points onthe formed edge of the seamless enclosure and cutting the inside edgeusing the plurality of optical reference points.

The invention relates in another embodiment to a method of centering aracetrack between a formed edge and an inside edge of a seamlessenclosure having a single open end, wherein the seamless enclosuresupports a handheld computing device having display portion located inthe single open end. The method is carried out by determining a centerpoint of the display portion, determining an angle of tilt of thedisplay portion, and cutting the inside edge based upon the center pointand the angle of tilt.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, wherein likereference numerals designate like structural elements, and in which:

FIGS. 1A-1B are perspective diagrams of a handheld computing device inits assembled form.

FIG. 1C is a cross sectional view of the housing highlighting the natureof the undercut geometry.

FIGS. 2A-2E are an exploded perspective diagrams of an electronic devicein its unassembled form.

FIG. 3A are view diagrams of the housing showing the racetrack.

FIGS. 4A-4B graphically illustrate centering a racetrack in accordancewith an embodiment of the invention.

FIGS. 5A-5C show low Z height integrated speaker system suitable for usein a small form factor electronic device.

FIGS. 6A-6B show audio jack opening in accordance with an embodiment ofthe invention.

FIGS. 7A-7C show assembly of G unit in accordance with an embodiment ofthe invention.

FIGS. 8A-8B show gas relief structures in accordance with an embodimentof the invention.

FIG. 9 shows a representative cross sectional view of the housing wherethe dock opening formed by folding over a portion of the housing inaccordance with an embodiment of the invention.

FIGS. 10A-10B shows a representative cross sectional view of the housingwhere the dock opening is to be created by way of apunching/forming/machining process.

FIGS. 11A-11C graphically illustrate the process for forming a shortspan opening in the housing.

FIGS. 12A-12C graphically illustrate the process for forming a long spanopening in the housing.

FIG. 13 shows a corner stiffener in accordance with an embodiment of theinvention

FIG. 14 shows representative sacrificial z alignment bumps pre and postmachining.

FIG. 15 shows a flowchart detailing a process for installing mountingbrackets into a housing in accordance with an embodiment of theinvention.

FIG. 16 shows a flowchart detailing a process for assembling the devicein accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to a preferred embodiment of theinvention. An example of the preferred embodiment is illustrated in theaccompanying drawings. While the invention will be described inconjunction with a preferred embodiment, it will be understood that itis not intended to limit the invention to one preferred embodiment. Tothe contrary, it is intended to cover alternatives, modifications, andequivalents as may be included within the spirit and scope of theinvention as defined by the appended claims.

The described embodiments relate to an aesthetically pleasing portableelectronic device. The portable electronic device is formed of a curvedseamless housing and an aesthetically pleasing polished flat top glasslayer. The uniformity of the appearance of the portable electronicdevice is enhanced since unlike conventional portable electronicdevices, the polished top glass layer is mounted to the seamless housingwithout the use of a bezel. The seamless nature of the housing and thelack of a bezel provide several advantages besides the uniform andappealing appearance. Such advantages include the fact that fewercomponents are required for assembly, the portable electronic device isable to more readily withstand the impact of drop event, and betterprotection is provided to the polished glass top layer and any sensitiveoperational components therein.

The seamless housing is formed from a single sheet of metal (such asstainless steel). The housing has an undercut geometry in which thelinear dimensions of an opening into which the operational componentsare inserted during assembly are smaller than the linear dimensions ofthe body of the housing itself. Moreover, the curvature of the housingis asymmetric in that an upper portion of the housing is formed to havea deep spline (i.e., higher curvature) whereas a lower portion of thehousing is formed to have a more shallow spline. This asymmetry aids ina user's tactile sensation in part because it provides a better fit tothe user's hand. Moreover, the metallic nature of the housing providesgood electrical grounding for built-in RF antenna as well as to mitigatethe effects of electromagnetic interference (EMI) and electrostaticdischarge (ESD).

Unlike the assembly of conventional portable electronic devices wherecomponents are assembled in a top-down manner (i.e., the components areinserted into the housing before the bezel is snapped on), the undercutgeometry of the housing requires that all components fit within thesmaller dimensions of the window opening in the housing. Moreover, theassembly of the portable electronic device is carried out in a bottom-upmanner using what is referred to as a blind assembly. In order tofacilitate the bottom-up, blind assembly of the portable electronicdevice and to minimize any offsets between the polished top glass layerand an uppermost portion of the housing (referred to as the racetrack),various techniques, apparatus and systems are presented that minimizestack (i.e., z direction) tolerance. For example, portions of bracketsused to mount subassemblies are welded to the housing and aresubsequently machined at the same time and with the same set up as atopmost portion of the housing. In this way accurate Z datums formounting various components are provided. It should be noted thatmachining is preferred since machined tolerances on the order of 0.05 mmcan be achieved whereas conventional weldment position tolerances aretypically on the order of 0.2 mm.

Other aspects of the invention relate to specific approaches tominimizing the Z height of the assembled components. In other words, inkeeping with both the aesthetic look and feel, the Z height of theportable electronic device is maintained to a value consistent withproviding a favorable user experience. This can be accomplished in anumber of ways in addition to those already discussed with regards to,for example, the mounting brackets. A minimum Z height speaker assemblycan be fabricated using a piezoelectric speaker in combination with ahorizontal acoustic barrier. Gaps in the horizontal acoustic barrierhave the effect of directing the sound produced by the piezoelectricspeaker to any desired location in the housing. For example, the soundcan be directed to specific openings in the housing otherwise unrelatedto the broadcasting of sound. Such openings can include for example adock opening and/or an audio jack opening. Enhancing the perceived soundby providing a back volume (i.e., using the back surface of the housingas a resonator) can be achieved using existing components and anappropriately placed back volume acoustic seal. In order to assure thatthe back volume seal integrity is maintained in spite of the variance inZ tolerance between the shield and housing changes from device todevice, adapters are placed in close proximity to the back volumeacoustic seal.

Other aspects of the invention that preserve the available Z heightrelate to the organization of circuits associated with the battery anddisplay screen. In particular, as described below battery and displayscreen circuitry co-exist in the same Y location thereby reducing theoverall Y component of the circuits. In the described embodiments, thebattery circuitry can include a battery safety circuit and the displaycircuitry can include a display controller (in the particularembodiments, the display is a liquid crystal display, LCD, and thecontroller is a LCD controller). Conventional designs dictate that thebattery safety circuit be placed in a central portion of the battery andthat the LCD controller not be aligned to a far edge of the display(this would likely increase line width and parasitic capacitancereducing the available drive of the LCD controller). Furthermore, inorder to conform to the spline of the housing and to reduce the overallZ of the product, the CD controller flex is bent around the battery.

Furthermore, providing gas relief structures on a plastic frame used tomount the protective glass layer enhances the adhesion of glass layer toplastic frame. Such structures can be formed by, for example, removingpredetermined sections of plastic frame in appropriate locations bypunching holes of a predetermined size and location. In this way, anytrapped gases, such as air, can escape providing a more uniformdistribution of adhesive resulting in a stronger and more reliable bondbetween the glass layer and the plastic frame.

These and other embodiments of the invention are discussed below withreference to FIGS. 1-16. However, those skilled in the art will readilyappreciate that the detailed description given herein with respect tothese figures is for explanatory purposes as the invention extendsbeyond these limited embodiments.

Throughout the following discussion, the term “CNC” is used. Theabbreviation CNC stands for computer numerical control and refersspecifically to a computer controller that reads computer instructionsand drives a machine tool (a powered mechanical device typically used tofabricate components by the selective removal of material). It should benoted however, that any appropriate machining operation can be used toimplement the described embodiments and is not strictly limited to thosepractices associated with CNC.

FIGS. 1A-1B are perspective diagrams showing various views of fullyassembled portable electronic device 10 in accordance with an embodimentof the invention. The portable electronic device 10 may be sized forone-handed operation and placement into small areas such as a pocket,i.e., the portable electronic device 10 can be a handheld pocket sizedelectronic device. By way of example, the electronic portable electronicdevice 10 may correspond to a computer, media device, telecommunicationdevice and/or the like. The portable electronic device 10 is capable ofprocessing data and more particularly media such as audio, video,images, etc. The portable electronic device 10 may generally correspondto a music player, game player, video player, personal digital assistant(PDA), and/or the like. With regards to being handheld, the portableelectronic device 10 can be operated solely by the user's hand(s), i.e.,no reference surface such as a desktop is needed. In some cases, thehandheld device is sized for placement into a pocket of the user. Bybeing pocket sized, the user does not have to directly carry the deviceand therefore the device can be taken almost anywhere the user travels(e.g., the user is not limited by carrying a large, bulky and heavydevice).

The portable electronic device 10 may be widely varied. In someembodiments, portable electronic device 10 may perform a single function(e.g., a device dedicated to playing and storing media) and, in othercases, the electronic device may perform multiple functions (e.g., adevice that plays/stores media, receives/transmits telephone calls/textmessages/internet, and/or performs web browsing). In some embodiments,the portable electronic device 10 is capable of communicating wirelessly(with or without the aid of a wireless enabling accessory system) and/orvia wired pathways (e.g., using traditional electrical wires). In someembodiments, the portable electronic device 10 may be extremely portable(e.g., small form factor, thin, low profile, lightweight). In somecases, the portable electronic device 10 may be sized for beinghandheld. The portable electronic device 10 may even be sized forone-handed operation and placement into small areas such as a pocket,i.e., the portable electronic device 100 can be a handheld pocket sizedelectronic device.

By way of example, the portable electronic device 10 may correspond toconsumer electronic products such as computers, media players, personaldigital assistants (PDA), telecommunication devices (phone), personale-mail or messaging devices and/or the like. In one example, theelectronic device may correspond to any of those electronic devices aniPod™, an iPod Nano™, an iPod Shuffle™, an iPod™ Touch or an iPhone™available by Apple Inc. of Cupertino, Calif.

The portable electronic device 10 includes a housing 100 configured toat least partially enclose any suitable number of components associatedwith the electronic portable electronic device 10. For example, thehousing may enclose and support internally various electrical components(including integrated circuit chips and other circuitry) to providecomputing operations for the device. The integrated circuit chips andother circuitry may include a microprocessor, memory, a battery, acircuit board, I/O, various input/output (I/O) support circuitry and thelike. Although not shown in this figure, the housing 100 may define acavity within which the components may be positioned and housing 100also may physically support any suitable number of mechanisms, withinhousing 100 or within openings through the surface of housing 100.

In addition to the above, the housing may also define at least in partthe outward appearance of portable electronic device 10. That is, theshape and form of the housing 100 may help define the overall shape andform of the portable electronic device 10 or the contour of the housing100 may embody the outward physical appearance of the portableelectronic device 10. Any suitable shape may be used. In someembodiments, the size and shape of the housing 100 may be dimensioned tofit comfortably within a user's hand. In some embodiments, the shapeincludes a slightly curved back surface and highly curved side surfaces.The shape will be described in greater detail below.

In one embodiment, the housing 100 is integrally formed in such as wayas to constitute is a single complete unit. By being integrally formed,the housing 100 has a seamless appearance unlike conventional housingsthat include two parts that are fastened together thereby forming areveal, a seam there between. That is, unlike conventional housings, thehousing 100 does not include any breaks thereby making it stronger andmore aesthetically pleasing.

The housing 100 can be formed of any number of materials including forexample plastics, metals, ceramics and the like. In one embodiment,housing 100 can be formed of stainless steel in order to provide anaesthetic and appealing look and feel as well as provide structuralintegrity and support for all sub-assemblies installed therein. Whenmetal, the housing 100 can be formed using conventional collapsible coremetal forming techniques well known to those skilled in the art.

The portable electronic device 10 also includes a cover 106 thatincludes a planar outer surface. The outer surface may for example beflush with an edge of the housing wall that surrounds the edge of thecover. The cover 106 cooperates with the housing 100 to enclose theportable electronic device 10. Although the cover can be situated in avariety of ways relative to the housing, in the illustrated embodiment,the cover 106 is disposed within and proximate the mouth of the cavityof the housing 100. That is, the cover 106 fits into an opening 108. Inan alternate embodiment, cover 106 may be opaque and may include touchsensing mechanism that forms a touch pad. Racetrack 122 is defined asthe uppermost portion of the housing 100 that surrounds the polished topglass layer 106. In order to maintain the desired aesthetic look andfeel of the portable electronic device 10, it is desirable that anyoffsets between the housing 100 and the polished top glass layer 106 beminimized and the racetrack 122 be centered.

The cover 106 may be configured to define/carry the user interface ofthe electronic device 10. The cover 106 may for example provide aviewing region for a display screen 104 used to display a graphical userinterface (GUI) as well as other information to the user (e.g., text,objects, graphics). The display screen 104 may be part of a display unit(not shown) that is assembled and contained within the housing 100. Thedisplay unit may for example be attached internally to a metal frame(e.g., 302). The cover may also provide a user clickable input button114 (home button) that can be used to provide a user input event to theportable electronic device 10. Such user input events can be used forany number of purposes, such as resetting the portable electronic device10, selecting between display screens presented on display screen 104,and so on. In one embodiment, the cover 106 is a protective top layer oftransparent or semitransparent material (clear) such that the displayscreen 104 is visible therethrough. That is, the cover 106 serves as awindow for the display screen 104 (i.e., the transparent cover overlaysthe display screen ). In one particular embodiment, the cover is formedfrom glass (e.g., cover glass), and more particularly highly polishedglass. It should be appreciated, however, that other transparentmaterials such as clear plastic may be used.

In one embodiment, the viewing region may be touch sensitive forreceiving one or more touch inputs that help control various aspects ofwhat is being displayed on the display screen. In some cases, the one ormore inputs can be simultaneously received (e.g., multi-touch). In theseembodiments, a touch sensing layer (not shown) can be located below thecover glass 106. The touch sensing layer may for example be disposedbetween the cover glass 106 and the display screen 104. In some cases,the touch sensing layer is applied to the display screen 104 while inother cases the touch sensing layer is applied to the cover glass 106.The touch sensing layer may for example be attached to the inner surfaceof the cover glass 106 (printed, deposited, laminated or otherwisebonded thereto). The touch sensing layer generally includes a pluralityof sensors that are configured to activate as the finger touches theupper surface of the cover glass 106. In the simplest case, anelectrical signal is produced each time the finger passes a sensor. Thenumber of signals in a given time frame may indicate location,direction, speed and acceleration of the finger on the touch sensitiveportion, i.e., the more signals, the more the user moved his or herfinger. In most cases, the signals are monitored by an electronicinterface that converts the number, combination and frequency of thesignals into location, direction, speed and acceleration information.This information may then be used by the portable electronic device 10to perform the desired control function relative to the display screen104.

The portable electronic device 10 can also include one or more switchesincluding power switches, volume control switches, user input devicesand the like. A power switch 110 can be configured to turn the portableelectronic device 10 on and off, whereas a volume switch 112 isconfigured to modify the volume level produced by the electronicportable electronic device 10. portable electronic device 10 portableelectronic device 10 The portable electronic device 10 may also includeone or more connectors for transferring data and/or power to and fromthe portable electronic device 10. The portable electronic device 10 mayincludes an audio jack 116 and a data/power connector 118. The audiojack 116 allows audio information to be outputted from the portableelectronic device 10 by way of a wired connector. The connector 118allows data to be transmitted and received to and from a host devicesuch as a general purpose computer (e.g., desktop computer, portablecomputer). The connector 118 may be used to upload or down load audio,video and other image data as well as operating systems, applicationsand the like to and from the portable electronic device 10. For example,the connector 118 may be used to download songs and play lists, audiobooks, photos, and the like into the storage mechanism (memory) of theportable electronic device 10. The connector 118 also allows power to bedelivered to the portable electronic device 10.

The connector 118 can receive an external corresponding connector (notshown) that is capable of plugging into a host device (and/or powersupply) in order to allow communications (e.g., data/power transfer)between the portable electronic device 10 and the host device. Theconnector may be widely varied. In one embodiment, the connector is aperipheral bus connector, such as a USB or FIREWIRE connector. Thesetype of connectors include both power and data functionality, therebyallowing both power delivery and data communications to occur betweenthe portable electronic device 10 and the host device when the portableelectronic device 10 is connected to the host device. In some cases, thehost device can provide power to the media portable electronic device 10that can be used to operate the portable electronic device 10 and/orcharge a battery included therein concurrently with the operating. Inone particular embodiment, the connector is a 30 pin connector as usedin many products manufactured by Apple Inc of Cupertino, Calif. Audiojack 116 can receive an audio post (not shown) that can provide audiosignals to external audio rendering devices, such as headphones,speakers, etc.

Although the device may connect through various wired connections, itshould be appreciated that this is not a limitation. In one embodiment,the electronic portable electronic device 10 also includes a mechanismfor wireless communications. For example, as shown, the portableelectronic device 10 may include an antenna (i.e., antenna 222). Theantenna may be disposed internal to the housing 100. The wirelesscommunications can be based on many different wireless protocolsincluding for example Bluetooth, RF, 802.11, and the like. In order tominimize any adverse impact on wireless communications in embodimentswhere the housing is metallic and therefore conductive, portableelectronic device 10, a portion of the housing 100 may replaced with aradio transparent cap 120 formed of a non-conductive material, such asplastic.

FIG. 1C shows a cross sectional view of the housing 100 highlighting thenature of the undercut geometry. Although in general the inner crosssectional shape of the housing 100 may be the same or different from theexternal cross sectional shape of the housing 100, the interior shape ofhousing 100 substantially conforms to the outer shape of housing 100.The housing 100 can be formed having an undercut geometry with curvaturethat more easily receives the hand of a user (e.g., form fits). Inparticular, an interior wall of housing 100 substantially conforms tothe shape of an exterior wall of housing 100. More specifically, sidewall 121 (both interior and exterior) is rounded and curved inwardly toform a concave undercut region 123 formed at an upper portion of theside wall 121 in proximity to cut edge 128. By undercut it is meant thatthe side wall 121 curves back inwardly towards the interior of thehousing 100. In this way, the window opening 108 has at least smaller Xdimension and Y dimension than does the body of the housing 100. In oneexample, the housing 100 can have dimensions of approximately(x,y)_(housing)=(61.8 mm, 111 mm) whereas the opening 108 can havedimensions of approximately (x,y)_(opening)=(58.3 mm, 107.5 mm).

FIGS. 2A-2E show various exploded perspective diagrams of the electronicportable electronic device 10 in its unassembled form. The portableelectronic device 10 includes housing 100 shown in FIG. 2A into whichare attached a number of operational and/or structural components.Housing 100 can take the form of a seamless enclosure. The seamlessnature of the housing 100 provides an aesthetic look and feel to theportable electronic device 10 as well as provides added resistance todeformation and possible damage to internal components caused by theimpact of a drop event. In the embodiments described herein, housing 100is formed of stainless steel and having thickness of approximately 0.5mm. It should be noted, however, that this configuration isrepresentative in nature only and does not provide limitationsconstraining the ultimate scope of the invention.

The housing 100 extends along a vertical (Y) axis and a horizontal (X)axis having a height Z. The housing 100 can be of various sizes. Forexample, the housing 100 can have a height (Z) of approximately 8.5 mm,an X dimension of approximately 61.8 mm and a Y dimension ofapproximately 111 mm. The housing 100 includes a cavity 124 which issized and dimensioned for the receipt of the internal components of theportable electronic device 10. The internal components are assembledthrough window opening 108. The undercut geometry of the housing 100provides that the linear dimensions of the window opening 108 into whichthe operational components are inserted during assembly are smaller thanthe linear dimensions of the body of the housing 100. For example, thewindow opening 108 can have an X dimension of approximately 58.3 mm anda Y dimension of approximately 107.5 mm.

One aspect of the desired look and feel is the symmetry in design andconformal appearance of portable electronic device 10. One aspect of thesymmetry of the portable electronic device 10 concerns the racetrack122. The racetrack 122 is the strip of metal around the cover 106 on thefront face of the device. The width of the racetrack 122 is defined byan outer racetrack profile and inner racetrack profile. Since thehousing 100 is made from a sheet metal material, the outer racetrackprofile is achieved by sheet metal forming while the inner racetrackprofile is achieved by machining where the forming tolerance is muchgreater than machining tolerance. In the described embodiment, the outerracetrack profile is consistent with a formed edge 126 whereas the innerracetrack profile is consistent with and cut edge 128 of housing 100 asillustrated in FIG. 3 showing a representative cross section and topview of portable electronic device 10 highlighting the relationship ofracetrack 122 and both the formed edge 126 and the cut edge 128.

In order to maintain the desired appearance of portable electronicdevice 10 it may be desirable to properly center racetrack 122. Thiscentering can however be accomplished in a number of ways depending uponwhat is considered to be an important factor in the overall aestheticsof the design of portable electronic device 10. In any case, a series ofoptical measurements are made using for example a CCD camera to measurethe outside racetrack profile after a rough cut of same. Once the CCDmeasurements have been taken, any of a number of approaches can be usedto center the racetrack 122. However, depending upon which approach istaken can result in somewhat different results. For example, as shown inFIG. 4A, centering the racetrack 122 using the outside racetrack profile(i.e., formed edge 126) will produce a consistent racetrack width,however, the gap 130 from the housing to glass will be less consistent.[gap 130 is not referenced] On the other hand, the racetrack 122 canalso be centered by forming the inner racetrack profile shape by cuttingthe cut edge 128 per the 3D CAD, but use the CCD measurements to findthe center (x₀, y₀) and any rotation angle φ for cutting the innerprofile as shown in FIG. 4B. This particular centering approach willgive a less consistent racetrack width but a more consistent gap 130from the housing to glass.

FIGS. 2B-2E illustrate the operational components of the portableelectronic device 10. In the described embodiment, the components of theportable electronic device 10 are organized in layers. The relationshipand organization of the components within each layer and relationshipbetween layers can be used to facilitate both the assembly andoptimization of Z height tolerances of the portable electronic device10. By minimizing Z height tolerances, the electronic portableelectronic device 10 is manufactured to be extremely compact, sturdy,aesthetically pleasing and ergonomic at relatively low cost. Forexample, the fact that the electronic portable electronic device 10 isassembled without the need of a bezel reduces manufacturing and assemblycosts. The layers can include a first (main electronic) layer 200, asecond (metal frame or M-frame) layer 300 and a third (glass or G unit)layer 400 each of which is described in more detail below.

FIG. 2B shows a detailed view of the first layer 200 (referred tohereinafter as PCB layer 200) in accordance with an embodiment of theinvention.

The PCB layer 200 includes a first assembly 204 and a second assembly206, which are physically and operatively connected via a flex circuit202. The first assembly 204 includes a printed circuit board (PCB) 205onto which the flex circuit 202 is attached. The printed circuit board205 is configured to carry multiple components including for exampleprocessor, memory and the like. The printed circuit board 205 is alsoconfigured to carry an RF shield 207 that is disposed over the variouscomponents. RF shield 207 is formed from metal and configured to coverand surround the components. The first assembly also includes a speakersystem 209 that is not a separate discrete system but rather a systemthat integrates with other components in order to properly output sound.At its core, the speaker system includes a piezo speaker 210, acousticseal 212 and acoustic barrier. The piezo speaker 210 is attached to theRF shield 207, the acoustic seal 212 closes off gaps in order to form anacoustic volume between RF shield and housing. This embodiment will bedescribed greater detail in FIGS. 5A-5C. The printed circuit board 205is also configured to carry the connector 118 and the audio jackassembly 116. In the described embodiment, the audio jack 116 fits intoaudio jack opening 117 and acts as an interface to an external circuit(such as head or earphones) by way of a wire or other type connector.For proper fit of the audio jack 116 into the audio jack opening 117,the audio jack opening 117 must have a shape that conforms to both thespline of the housing 100 as well as the shape of the audio jack 116described in more detail in FIGS. 6A-6B.

The PCB layer 200 can be fitted into cavity 124 of housing 100 andsecured to an interior wall of the housing 100 using fasteners such asscrews 208 a and 208 b that connect directly to housing 100 (it shouldbe noted that screw 208 b also facilitates RF antenna groundingdiscussed in more detail below). It should be noted that prior toassembly, the power button 110 is attached to the housing using a powerbutton plate 228 and the volume button 112 is attached to the housing110 using a volume button plate 230 each of which are electricallyconnected to each other by way of flex 232.

One of the problems with having an active RF antenna assembly in a closeproximity to a number of active circuits is the generation ofelectromagnetic interference (EMI) that can detune or otherwiseadversely affect the performance of the RF antenna 222. For example, therelatively long conductors present in the flex 202 can act as a sourceof EMI that can detrimentally affect the performance of RF antenna 222.In order to substantially reduce or even eliminate this source of EMI itwould be desirable to RF ground the PCB 200. Therefore, in order toprovide a good RF ground, portions 226 of the insulating layer of flex202 facing the inside surface of housing 100 are removed in order toexpose the conductive layer therein. The portions 226 of the flex 202that are removed typically are those regions that are relatively largeand contiguous thereby having the greatest potential to provide good RFgrounding when placed in contact with the metal of housing 100. In thedescribed embodiment, after the portions 226 of the flex 202 have beenremoved, the exposed conductive material is pressed down onto thehousing 100. The presence of pressure sensitive conductive adhesive(PSCA) placed between flex 202 and housing 100 provides the requisitemechanical and electrically conductive bond. In addition to providinggood RF grounding, the conformance of the flex 202 to the inside surfaceof housing 100 reduces the overall Z profile of the PCB 200.

FIGS. 2C and 2D show a un-assembled top view and an assembled bottomview of third layer 300 referred to hereinafter as metal (M) frameassembly 300, respectively, in accordance with an embodiment of theinvention. Turning first to FIG. 2C, M-frame assembly 300 can includeM-frame 302, battery 304 attached to the M-frame 302 by way of pressuresensitive adhesive (PSA) and display circuit 306 that includes display104. In the described embodiment, Z height requirements for the M-frame300 can be reduced by using what is referred to as half shears 310. Halfshears 310 can be formed by removing portions of the M-frame 302 inthose locations around screw holes in M-frame 300 used to accommodatescrews 312 a and 312 b that attach M-frame 302 to housing 100. In thedescribed embodiment, a sufficient amount of material is removed fromM-frame 302 such that a top portion of each of the screws 312 a and 312b are essentially flush with a top surface 314 of the M-frame 302. Asdescribed in more detail below, each half shear 310 is aligned with a Zheight datum bump described in more detail below thereby furtherminimizing Z height requirements for portable electronic device 10.Moreover, display unit alignment holes 316 are provided to acceptalignment pins (not shown) on display unit 306 that provide x,yalignment to the housing 100 by way of alignment holes 140 in mountingbrackets 136 a and 136 b.

In addition to minimizing Z height requirements, the overall Y componentof battery circuits and display circuits can be reduced as shown in FIG.2D that graphically illustrates the organization of circuits associatedwith the battery 304 and display circuit 306. In particular, batterycircuitry 318 and display circuitry 320 co-exist in the same Y locationthereby reducing the overall Y component of the circuits. In thedescribed embodiments, the battery circuitry 318 can take the form of abattery safety circuit 318 and the display circuitry can include a LCDcontroller 320. Conventional designs dictate that the battery safetycircuit 318 be placed in a central portion of the battery 304 and thatthe LCD controller 320 should not be aligned to a far edge of thedisplay circuit 306 (as this would likely increase line width andparasitic capacitance reducing the available drive of the LCDcontroller). However, by modifying the design of both battery safetycircuit 318 and LCD controller 320, the two circuits can be placed atthe same Y location. In this way, the overall Y component of the twocircuits taken together can be reduced. Furthermore, in order to conformto the spline of the housing 100 and to reduce the overall Z of theportable electronic device 10, the LCD controller flex 322 is wrappedaround and placed under the battery 304 in order for display connector324 and battery connector 326 to mate as shown in FIG. 2D.

Portable electronic device 10 includes glass, or G, unit 400 shown inFIG. 2E. G unit 400 includes cover glass 106. G unit 400 also includescover glass PSA 404 used to adhere cover glass 106 plastic frame 406.Environmental seal 408 can be used to prevent dust or other unwantedenvironmental contaminants from entering the portable electronic device10 after assembly. During assembly, G unit 400 can be placed withinwindow 108 of housing 100 on top of the M-frame assembly 300 as shown inFIGS. 8A-8C. The G unit 400 self aligns during the insertion process andsecured to M frame 302 using M-frame lead in 324. G unit 400 includes adouble shot arrangement formed of plastic frame 406 and anenvironmental, or cosmetic, seal 408 made of, for example, thermoplasticurethane (TPU), rubber, and the like that can act to protect portableelectronic device 10 from dust and or moisture. As described below, theshape of environmental seal 408 in relation to housing 100 aids in selfaligning G unit 400 to window 108 opening during assembly. During theassembly process as shown in FIG. 8A, the G unit 400 is inserted intowindow opening 108 by bringing plastic frame 406 into contact withM-frame lead in 324. In the described embodiment, both the environmentalseal 408 and the M-frame lead in 324 have corresponding tapered shapesthat provide for the G unit 400 to self align. For example, in FIG. 8B,as the G unit 400 is being inserted into the window opening 108, theplastic frame 406 encounters the tapered shape of the M-frame lead in324. The M-frame lead in 324 has the effect of both aligning andsecuring the G unit 400 until such time as shown in FIG. 8C that thetapered edge of the environment seal 408 encounters the inside, or cutedge, 128 of the housing 100. A portion 410 of the environmental seal408 extends beyond the cut edge 128. In the described embodiment, theportion 410 has a tapered edge that causes the G unit 400 to self centerto the window opening 108 as shown in FIG. 8C until the G unit 400 iscaptured by M-frame lead in 324.

During assembly, when pressure is applied to G unit 400, trapped gasescoalesce into gas bubbles having the result of minimizing the bond areabetween the pressure sensitive adhesive (PSA) and the glass 106. The gasbecome trapped due in part to the fact that due to assembly tolerances,the PSA would touch the seal 402 closing off a gas escape route(see FIG.9A). Therefore, it would be advantageous to provide gas reliefstructures or assembly techniques on plastic frame 406 thereby enhancingthe adhesion of glass layer 106 to plastic frame 406. Gas relieftechniques can include removing predetermined sections of plastic frame404 in appropriate locations by for example punching holes of apredetermined size and location or by removing small amounts of PSA fromcorners of the portable electronic device 10 allows trapped gas toescape more easily as shown in FIG. 9B. In this way, a more uniformdistribution of adhesive resulting in a stronger and more reliable bondbetween glass layer 106 and plastic frame 404 can be achieved.

FIG. 5A shows an integrated, or minimum Z height speaker assembly 500which is a particular embodiment of the integrated speaker assemblyshown in FIG. 2B. The minimum Z height speaker assembly 500 includes atleast a piezoelectric speaker 210 in combination with acoustic seal 212and a horizontal (Y) acoustic barrier 502. Gaps 504 in the acoustic sealhave the effect of directing the sound produced by the piezoelectricspeaker 210 to any desired location in the housing 100. For example, thesound can be directed to specific openings in the housing 100 otherwiseunrelated to the broadcasting of sound. Such openings can include forexample dock opening 119 and/or an audio jack opening 117. Thehorizontal acoustic barrier 502 ensures that substantially no soundleaks to undesired portions of the housing 100 such as gaps associatedwith the volume button 112, power button 110, or the antenna cap 120.Furthermore, as shown in FIG. 5B, a back volume seal 506 can form anacoustic cavity 508, also referred to as a back volume, in cooperationwith the housing 100. In this way, by using existing components, Zheight requirements for creating the back volume 508 are reduced and abackside portion of the housing 100 can act as a resonator arranged toenhance the audio experience of a user. Since the back volume 508 iscreated using existing components (i.e., housing 100 and acousticbarrier 502), there is no adverse impact on the overall Z height of theportable electronic device 10.

FIG. 5C shows selected crush zones 510 that are provide for adjustmentsfor variations in Z tolerances and assure the integrity of the backvolume 508. During assembly of portable electronic device 10, pressurecan be exerted onto PCB 200 that has the effect of compressing, orcrushing, crush zones 510. In this way, any variations in Z height ofthe various components of PCB 200 can be accommodated without comprisingthe integrity of the back volume 508. It should be noted that crushzones 510 can take on any of a number of shapes and sizes and be formedof any resilient material able to form a seal between the housing 100and the back volume seal 506.

As shown in FIG. 6A, one of the problems with the asymmetric geometry ofthe housing 100 is that as the bottom cut surface (point “A”) of audiojack opening 117 moves up in the positive Z direction, the edge of thecut moves in a negative Y direction due to the high curvature of thehousing 100. In other words, a small change in the positive Z directionresults in a large change in the negative Y direction. Since the audiojack 116 is fixed in the Z direction, the size of the audio jack opening117 must not come so close to the upper portion of the housing 100 so asto present a risk to the cover glass 106 as would be the case if theaudio jack opening 117 were formed too far into the shallower portion ofthe housing 100. In any case, having a fully circular portion in theshallower geometry of the housing 100 can result in very sharp edges (asshown in FIG. 6A) that must be machined down. Conventional machiningprocesses, however, would cause the housing 100 in that region to becomeunacceptably thin presenting a risk of damage in an impact event.Therefore, in order to accommodate the circular shape of audio jack 116,the spline of housing 100, as well as to decrease the audio jack trim(the material around the audio jock structure itself) as little aspossible, an non-symmetric audio jack opening 117 is formed as shown inFIG. 6B having circular portion 602 and a non circular portion 604providing the non-symmetric shape for audio jack opening 117. In thisway, the audio jack opening 117 provides that the audio jack 116 and theaudio jack opening maintains a centered and circular appearanceespecially when viewed from above. It should be noted that it has beendiscovered that subsequent to the forming of the audio jack opening 117in this manner, a deburring process for touch up can be performed usingmaterials considered unconventional in the art of deburring. Suchmaterials can include, for example, a bamboo wooden stick, woodenchopsticks, and the like.

In order to accommodate various interfaces (dock, audio jack, volume,power, for example), openings of various sizes must be created in thehousing 100. There are a number of approaches that can be used to createthese openings and make the opening trim appear to be thicker than thethickness (0.5 mm) of the sheet metal used to create the housing 100.One approach relies upon drawing or folding the sheet metal that formsthe housing 100 as shown in FIG. 9. In any case, creating these openingsin the housing 100 can result in long and thin webs of metal that candeform from the impact of a drop event, for example. In order toreinforce these areas, any of a number of different techniques can beused to add an additional layer of material (referred to as childmaterial) to the parent material, which in this case is stainless steelhaving an approximate thickness of 0.5 mm. In some embodiments, thechild material can be bonded to the parent material by welding,soldering, brazing or gluing. Once the child material is bonded to theparent material, a one stage cut is performed (machine or laser cut orpunch, for example) in order to create the actual hole geometry.

FIGS. 10A-10B shows a representative cross sectional view of the housing100 in the area of the dock opening 119. However, due to the thickness(approximately 0.5 mm), the material (stainless steel) from which thedescribed housing is formed, and the geometry (i.e., deep spline) of thehousing 100 obtaining the desired deep cut is difficult to achieve in alarge scale manufacturing environment. In particular, looking at FIG.10A, due to the geometry of the housing 100 using a conventionalpunching operation to create the dock opening 119 would result inunacceptable asymmetric cut between the steep spline of the top portionand shallower spline of the lower portion of housing 100. Therefore asillustrated in FIG. 10A, a metal support bracket 1002 having a thicknessapproximately that of the housing 100 (which in this embodiment isapproximately 0.5 mm) can be attached to the inside wall of housing 100using solder or braze material or glued. By using solder or brazematerial or glue, the support bracket 1002 can be securely attached tothe housing 100 as well as provides a good cosmetic result since thesolder or braze material obscures the gap between the housing 100 andsupport bracket 1002. FIG. 10B shows a result of the punching operationto form the dock opening 119. By using the support bracket 1002, adouble wall is formed in the area of the housing 100 in which the dockopening 119 (or any opening in housing 100 for that matter). In thedescribed embodiment, since any gaps between support bracket 1002 andhousing 100 are filled with solder or braze, both the desired cosmeticappearance and the desired structural integrity and strength can bemaintained. It should be noted that in order to provide optimal strengthfor holes having large spans (volume button opening), the respectivesupport brackets are positioned such that the presumptive hole ispositioned approximately midway of the support bracket.

FIGS. 11A-11C graphically illustrate the process for forming the dockopening. FIG. 11A illustrates the placement of support bracket 1002 onhousing 100 in relation to proposed dock opening 117. The supportbracket 1002 can be welded to housing 100. FIG. 11B shows in profileview juxtaposition of support bracket 1002 and proposed dock opening. Inthis case, the support bracket 1002 covers the entire area of theproposed dock opening in order to provide maximum support post CNC.Accordingly, FIG. 11C shows in profile the post punching operation andCNC of dock opening 119, the support bracket 1002 having an upperportion 1102 and a lower portion 1104. It should be noted that in orderto cosmetically hide the gap between the support bracket and housing100, solder or braze material can be used to fill any gaps post CNC.

In the case of openings having long spans, such as the volume controlbutton, FIGS. 12A-12C graphically illustrate the process for forming along span opening such as the volume button opening. FIG. 12Aillustrates the placement of support bracket 1202 on housing 100 inrelation to proposed volume button opening. It should be noted that inthis case, the support bracket 1202 only extends approximately midway inthe y direction since the primary area requiring support is that thinstrip 1204 above the proposed volume control button. The thin strip 1204is susceptible to deformation during an impact event. FIG. 12B shows aprofile view of the juxtaposition of the support bracket 1202, thehousing 100, and the proposed location of the volume control button.FIG. 12C shows the post laser cut of the volume control buttonillustrating the upper support bracket providing the requisite supportfor any long span openings in housing 100 such as volume button.

It should be noted, however, that the above procedures are predicated onmaterials, such as stainless steel, and geometries (i.e., those havesteep splines) that are not conducive to providing symmetric cuts or theproper depth of cut in a punching type operation. However, it iscontemplated that using material other than stainless steel, such asaluminum, can provide the requisite symmetry. In these cases, a onepiece punch and CNC can be used. It should further be noted that thethickness of the support brackets can be varied but it is found thathaving a thickness approximate to that of the housing 100 works well.

In order to prevent interference with RF antenna 222, housing materialis removed from housing 100 to form antenna hole 126. The antenna hole126 by removing conductive housing material using a laser and replacedwith non-conducting material such as plastic to form antenna cap 120. Inthis way, the interference caused by the presence of a conductingmaterial such as metal in the immediate vicinity of RF antenna 222 iseliminated. However this cutting away may cause the corner portion 128of the housing 100 to become weakened to the point where it becomessusceptible to deformation or damage due to an impact event. Therefore,a corner stiffener 130 can be used to provide structural support for thecorner portion 128 of the housing 100 by reinforcing the sidewall ofhousing 100 of the corner portion 128 as shown in FIG. 13. Cornerstiffener 130 is welded to or otherwise attached to housing 100.However, in contrast to other support brackets such as those for volumebutton and dock, the corner stiffener 130 serves two purposes, one toprovide additional structural integrity to the corner 128 of housing 100where material is to be removed and another as a ground for RF antenna222. In the described embodiment, antenna ground 132 is connected to RFantenna 222 by way of antenna screw 208 b. In order to provide goodelectrical connection between RF antenna 222 and corner stiffener 130,antenna ground 132 must remain substantially intact both in order tomechanically receive antenna screw 208 b and provide good electricalcontact to corner stiffener 130 (and housing 100).

Due to the size and location of antenna hole 126, a laser is used toremove the necessary amount of material from the housing 100 to form theantenna hole 126. However, the antenna ground 132 extends into theregion in close proximity to the material to be lasered off. Sinceantenna ground 132 must remain relatively intact, antenna ground 132 isprotected against any dross generated by the laser removing material toform the antenna hole 126 by a shield formed of for example, foam, orany other protective material that can be easily removed subsequent tothe forming of antenna hole 126.

Returning to FIG. 2A showing a detailed view of housing 100. As shown,the housing 100 includes a number of attachment fixtures used forattaching subassemblies to housing 100. Such attachment features caninclude, for example, PCB subassembly securing fixtures 134 a and 134 b,and 134 c that can be used to attach PCB assembly 200 to housing 100using fasteners such as screws 310 b and screw 208 a, respectively. Itshould be noted that screws 310 b attach M-frame assembly 300 and PCB200 to housing 100 using fixtures 134 a and 134 b unlike screws 310 athat attach M-frame assembly 300 directly to mounting brackets 136 a and136 b. As discussed above, RF ground 132 is used to both secure PCB 200to housing 100 as well as provide a ground plane for RF antenna 222.

Mounting brackets 136 a and 136 b are used to secure M-frame subassembly300 to housing 100. However, conventional approaches to attachingmounting brackets to housing 100 utilize high temperature attachingprocesses, such as laser welding, that can and usually do result incosmetic damage to the exterior surface of the housing 100. Thiscosmetic damage can require expensive and time consuming remediation,such as polishing, that can increase the cost of and time required toassembly the portable electronic device 10. Therefore, in order to avoidthe creation of the cosmetic damage, only low temperature attachmentprocesses are used to attach mounting brackets 136 a and 136 b tohousing 100. In order to eliminate cosmetic damage caused by hightemperature attachment processes (such as laser welding), mountingbrackets 136 a and 136 b are placed in appropriate locations on insidesurface of housing 100 using a low temperature weld process. Oncepositioned, mounting brackets 136 a and 136 b are securely attached toinside surface of housing 100 using a low temperature solder process. Byusing low temperature weld and solder processes, any damage, cosmetic orotherwise, to external surface of housing 100 that would have beencaused by the attachment of mounting brackets 136 a and 136 b to housing100 using conventional methods such as high temperature processes iseliminated. Therefore, in contrast to the conventional approach of usinghigh temperature attachment processes, using low temperature attachmentprocesses eliminates the necessity to perform a post attach polishing orother remediation on the exterior surface of the housing 100. In thisway, the aesthetic look and feel of portable electronic device 10 ispreserved. In this way, the mounting brackets 136 a and 136 b providereference surfaces for receiving and supporting some portion of theinternal components. Furthermore, the mounting brackets 136 a and 136 bprovide Z datum bumps 138 that minimize Z height, or stack, tolerance ofthe assembled internal components discussed in more detail below.

During the assembly of portable electronic device 10, the PCB 200,M-frame assembly 300 and G unit 400 are placed one atop the other duringwhat is referred to as a blind assembly operation in which each layermust align with each every other layer with minimum Z height tolerance.As well known in the art, whenever a manufacturing operation requires anumber of different setups, each separate setup has an associatedtolerance each of which is added to all the other tolerances. Byminimizing the number of setups in a manufacturing operation, the totalZ height tolerance for the operation can be kept to a minimum.Therefore, in order to minimize Z height tolerances in the assembly ofportable electronic device 10, a number of novel approaches have beendevised. For example, in order to minimize the Z height tolerance inattaching the M-frame assembly 300 to the housing 100, the mountingbrackets 136 a and 136 b include the aforementioned Z datum bumps 138(where two Z datum bumps are located on either side of M-frame screwhole 146). It should be noted that the Z datum bumps 138, the machinedtop surface 140 of the housing 100, and display unit alignment holes 142are machined at the same time using a single set up (as illustrated inFIG. 14). In this way, a Z height tolerance in relation to the topsurface 140 of the housing 100 of approximately 0.05 mm can be achieved(compared to a Z height tolerance of approximately 0.2 mm using astandard soldering approach with multiple set ups).

FIG. 15 shows a flowchart detailing a process 1500 for installingmounting brackets into a housing in accordance with an embodiment of theinvention. The process 1500 begins at 1502 by providing mountingbrackets having sacrificial z adjustment bumps located thereon. In thedescribed embodiment, the z adjustment bumps are arranged to have aportion of which can be machined away during a subsequent machiningprocess during which a top portion of the housing is also machined off.At 1504, the mounting brackets are positioned within the housing using alow energy attachment process such as a low energy weld. Next at 1506,the positioned brackets are soldered in place. The following operationsare performed during a single set up, where at 1508 the top portion ofthe housing is machined off, the sacrificial portion of the z adjustmentbumps is removed at 1510, and display unit x,y alignment holes aredrilled in the bracket at 1512.

FIG. 16 shows a flowchart detailing a process 1600 for assembling theportable electronic device 10 in accordance with an embodiment of theinvention. Firstly, at 1602, a pre-assembled housing is received. In thedescribed embodiment, the housing has had all appropriate openingsformed, support brackets and attachment fixtures affixed thereto. At1604, the PCB assembly is placed within the housing cavity. Since thewindow opening is smaller than the housing body, the insertion of thePCB assembly is done by inserting either the first or the second portionfirst followed by the remaining portion. For example, when inserting thePCB assembly, if the first portion of the PCB assembly is insertedfirst, then the dock and the audio jack are inserted into theirappropriate openings in the housing. Once the dock and the audio jackare properly seated, then the second portion of the PCB assembly isinserted, which in this case includes the RF antenna assembly. Once thePCB assembly is in place, then a portion of the conductive layer of theflex portion of the PCB assembly is exposed at 1606. It should be notedthat this step can be performed anytime prior to the insertion of thePCB into the housing. By exposing a portion of the conductive layer ofthe flex portion, an RF ground plane can be established by the housing.Once the conductive layer of the flex portion has been exposed, the PCBassembly is secured to the housing at 1608. In the described embodiment,the PCB assembly can be secured using screws to attach the first portionof the PCB assembly including the dock and the audio jack to the housingdirectly using PCB attachment fixtures. Once the PCB has been secured tothe housing, the exposed conductive layer of the flex is conformallypressed to the inside surface of the housing at 1610. In the describedembodiment, pressure sensitive conductive adhesive can be used to adherethe exposed portions to the housing. In addition to providing a goodelectrical contact thereby providing a good RF ground, by pressing theflex onto the inside surface of the housing, the flex is mechanicallysecured to the housing and also the amount of space taken up by the flexis concomitantly reduced.

Once the PCB is in place and secured, a pre-assembled M-frame andbattery are received at 1612. By pre-assembled it is meant that thebattery has already been attached to the M-frame by way of the pressuresensitive adhesive (PSA). At 1614, the display unit is placed upon theside of the M-frame opposite to that of the battery. It should be notedthat the display unit is not attached to the M-frame at this point sincethe display unit must be tilted up in order to gain access to thedisplay flex. The display flex is then placed under the battery andelectrically connected to the battery electrical connector at 1616. Oncethe battery and the display unit have been electrically connected toeach other, the M-frame assembly, including the battery and the displayunit are secured to the housing using a number of available screws at1618. Again since the display unit is not attached directly to theM-frame, the display unit is lifted in order to gain access to the screwholes in the M-frame.

It should be noted that in the described embodiment, a number of theavailable screws used to attach the M-frame assembly to the housingutilize mounting brackets attached directly to the housing. Thesemounting brackets include a number of Z height datum bumps that providea Z reference for M-frame assembly. In addition, some of the remainingavailable screws are used to attach the M-frame assembly as well as thePCB to the housing. Once the M-frame has been secured to the housing,the display unit is aligned using a number of alignment pins placeddiagonally from each other on either side of the display unit at 1620.The alignment pins can be used to mate with alignment holes in themounting brackets. At 1622, the touch panel is electrically connected tothe battery and at 1624, the glass unit is inserted into the windowopening and secured to the M-frame at 1626.

While this invention has been described in terms of several preferredembodiments, there are alterations, permutations, and equivalents, whichfall within the scope of this invention. It should also be noted thatthere are many alternative ways of implementing the methods andapparatuses of the present invention. For example, although an die castprocess is preferred method of manufacturing the seamless enclosure, itshould be noted that this is not a limitation and that othermanufacturing methods may be used. It is therefore intended that thefollowing appended claims be interpreted as including all suchalterations, permutations, and equivalents as fall within the truespirit and scope of the present invention.

1. A handheld electronic device, comprising: a single seamless metalhousing having a front opening; and a cover glass disposed within thefront opening and attached to the seamless housing without a bezel; adisplay unit disposed within the cavity of the metal housing; a displayscreen of the display unit being visible through the cover glass; and asubstantially transparent touch sensing layer disposed between the coverglass and the display screen of the display unit.
 2. The electronicdevice as recited in claim 1, the single seamless housing having anintegral bottom and side walls that cooperate to form a cavity incooperation with the front opening, the bottom wall having a curvedbottom surface, the side walls being rounded such that they form acurved side surface and an undercut within the cavity, an inside edge ofthe side walls surrounding and defining the front opening.
 3. Theelectronic device as recited in claim 2, the cover having a flat topsurface and being disposed within the cavity at the front opening, thecover substantially filling the front opening between the side walls,the flat top surface being substantially flush with an upper surface ofthe edge of the side walls.
 4. (canceled)
 5. The electronic device asrecited in claim 1 wherein the housing is formed from polished stainlesssteel. 6.-7. (canceled)
 8. The electronic device as recited in claim 1wherein the cover includes an opening for an input mechanism.
 9. Theelectronic device as recited in claim 2 wherein the cover is attached toa frame, and wherein the frame is mounted to the housing within thecavity of the housing.
 10. The electronic device as recited in claim 2,wherein the seamless housing comprises: an outside edge; a mountingbracket attached to the bottom wall suitable for securing an electronicassembly to the bottom wall of the housing; and an opening in at leastone sidewall having a depth of trim at least greater than that providedby the housing alone.
 11. The electronic device as recited in claim 10,further comprising: a racetrack, wherein racetrack is an uppermost flatportion of the housing between the inside edge and the outside edge. 12.The electronic device as recited in claim 11, wherein the mountingbracket includes at least one mounting bracket datum bump arranged toreduce Z height tolerance between the secured electronic assembly andthe racetrack.
 13. The electronic device as recited in claim 12, whereinthe Z height tolerance between the secured electronic assembly and theracetrack is reduced by forming the at least one mounting bracket datumbump and the racetrack in a single machining operation using a singlemachine setup.
 14. The electronic device as recited in claim 10 furthercomprising: prior to the machining of the opening in the side wall,attaching a secondary plate attached to the interior portion of the atleast one sidewall at the position of the opening, wherein the secondaryplate increases the depth of trim of the machined opening beyond thatprovided by the housing alone, wherein if the opening has a long andthin web section, then reinforcing the long and thin web section byadding a stiffener bracket.
 15. The electronic device as recited inclaim 14, wherein the opening in the sidewall is formed by metalforming, wherein the metal forming increases the depth of trim of theopening beyond that provided by the housing alone.
 16. The electronicdevice as recited in claim 12, wherein the racetrack is centered byoptically determining a plurality of reference points on the formed edgeof the seamless housing and cutting the inside edge using the pluralityof optical reference points.
 17. The electronic device as recited inclaim 12, wherein the racetrack is centered by determining a centerpoint and an angle of tilt of the top opening and cutting the insideedge based upon the determined center point and the angle of tilt. 18.The electronic device as recited in claim 10, wherein the mountingbracket comprises: a plurality of sacrificial z adjustment bumps havinga sacrificial portion arranged along the length of the mounting bracketwherein after the mounting bracket is attached to the bottom wall of theseamless housing, a top most portion of the seamless seamless housingand the sacrificial portion of the sacrificial Z adjustment bumps aremachined off concurrently with a drilling a plurality of XY alignmentholes, wherein the machining and the drilling are performed in a singlemachine set up. 19.-22. (canceled)
 23. A handheld electronic device,comprising: a single seamless housing having a front opening and anintegral bottom and side walls that cooperate to form a cavity incooperation with the front opening, the bottom wall having a curvedbottom surface, the side walls being rounded such that they form acurved side surface and an undercut within the cavity, an inside edge ofthe side walls surrounding and defining the front opening; and a coverdisposed within the front opening and attached to the seamless housingwithout a bezel.
 24. The handheld electronic device as recited in claim23, wherein the single seamless housing comprises: an outside edge; amounting bracket attached to the bottom wall suitable for securing anelectronic assembly to the bottom wall of the housing; and an opening inat least one sidewall having a depth of trim at least greater than thatprovided by the housing alone.
 25. The handheld electronic device asrecited in claim 24, wherein the mounting bracket includes at least onemounting bracket datum bump arranged to reduce Z height tolerancebetween the secured electronic assembly and the racetrack.
 26. Thehandheld electronic device as recited in claim 25, wherein the Z heighttolerance between the secured electronic assembly and the racetrack isreduced by forming the at least one mounting bracket datum bump and theracetrack in a single machining operation using a single machine setup.27. The handheld electronic device as recited in claim 23 furthercomprising: prior to the machining of the opening in the side wall,attaching a secondary plate attached to the interior portion of the atleast one sidewall at the position of the opening, wherein the secondaryplate increases the depth of trim of the machined opening beyond thatprovided by the housing alone, wherein if the opening has a long andthin web section, then reinforcing the long and thin web section byadding a stiffener bracket.
 28. The handheld electronic device asrecited in claim 27, wherein the opening in the sidewall is formed bymetal forming, wherein the metal forming increases the depth of trim ofthe opening beyond that provided by the housing alone.
 29. Theelectronic device as recited in claim 23, wherein the mounting bracketcomprises: a plurality of sacrificial z adjustment bumps having asacrificial portion arranged along the length of the mounting bracketwherein after the mounting bracket is attached to the bottom wall of theseamless housing, a top most portion of the seamless seamless housingand the sacrificial portion of the sacrificial Z adjustment bumps aremachined off concurrently with a drilling a plurality of XY alignmentholes, wherein the machining and the drilling are performed in a singlemachine set up.
 30. A handheld electronic device, comprising: a singleseamless metal housing having a front opening; and a cover glassdisposed within the front opening and attached to the seamless housingwithout a bezel; and a racetrack, the racetrack being a region between aformed edge and an inside edge of the seamless housing wherein theracetrack is centered with respect to the formed edge by determining acenter point of the display portion, determining an angle of tilt of thedisplay portion, and cutting the inside edge based upon the center pointand the angle of tilt.
 31. The handheld electronic device as recited inclaim 30, wherein the racetrack is defined by an outer racetrack profileand an inner racetrack profile.
 32. The handheld electronic device asrecited in claim 30, wherein the metal housing is formed of sheet metal.33. The handheld electronic device as recited in claim 30, wherein theouter profile of the racetrack is created by forming the sheet metal andthe inner racetrack is formed by machining, wherein the tolerance of theforming the sheet metal is greater than that of the machining.
 34. Ahandheld electronic device, comprising: a single seamless metal housinghaving a front opening; and a cover glass disposed within the frontopening and attached to the seamless housing without a bezel; and aracetrack, the racetrack being a region between a formed edge and aninside edge of the seamless housing wherein the racetrack is centeredwith respect to the formed edge by optically determining a plurality ofreference points on the formed edge of the seamless enclosure andcutting the inside edge using the plurality of optical reference points.35. The handheld electronic device as recited in claim 34, wherein theracetrack is defined by an outer racetrack profile and an innerracetrack profile.
 36. The handheld electronic device as recited inclaim 35, wherein the metal housing is formed of sheet metal.
 37. Thehandheld electronic device as recited in claim 36, wherein the outerprofile of the racetrack is created by forming the sheet metal and theinner racetrack is formed by machining, wherein the tolerance of theforming the sheet metal is greater than that of the machining.
 38. Thehandheld electronic device as recited in claim 37 wherein the opticallydetermining a plurality of reference points on the formed edge of theseamless enclosure comprises: taking a series of optical measurementsusing a camera to measure the outside racetrack profile after a roughcut of the outside racetrack profile is complete.
 39. The handheldelectronic device as recited in claim 38, wherein the racetrack iscentered by forming the inner racetrack profile shape by using theoptical measurements to find a center (x₀, y₀) and a rotation angle pfor cutting the inner profile.